218428733 has 4 divisors (see below), whose sum is σ = 231277500. Its totient is φ = 205579968.

The previous prime is 218428711. The next prime is 218428751. The reversal of 218428733 is 337824812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 91145209 + 127283524 = 9547^2 + 11282^2 .

It is a cyclic number.

It is not a de Polignac number, because 218428733 - 2⁸ = 218428477 is a prime.

It is a super-2 number, since 2×218428733² = 95422222799970578, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218428703) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6424358 + ... + 6424391.

It is an arithmetic number, because the mean of its divisors is an integer number (57819375).

Almost surely, 2^218428733 is an apocalyptic number.

It is an amenable number.

218428733 is a deficient number, since it is larger than the sum of its proper divisors (12848767).

218428733 is a wasteful number, since it uses less digits than its factorization.

218428733 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12848766.

The product of its digits is 64512, while the sum is 38.

The square root of 218428733 is about 14779.3346602613. The cubic root of 218428733 is about 602.2404504086.

The spelling of 218428733 in words is "two hundred eighteen million, four hundred twenty-eight thousand, seven hundred thirty-three".